module.exports={
  stringToArrayBuffer:stringToArrayBuffer,
  arrayBufferToString:arrayBufferToString,
}

function arrayBufferToString(arr){
  if(typeof arr === 'string') {  
      return arr;  
  }  
  var dataview=new DataView(arr.data);
  var ints=new Uint8Array(arr.data.byteLength);
  for(var i=0;i<ints.length;i++){
    ints[i]=dataview.getUint8(i);
  }
  arr=ints;
  var str = '',  
      _arr = arr;  
  for(var i = 0; i < _arr.length; i++) {  
      var one = _arr[i].toString(2),  
          v = one.match(/^1+?(?=0)/);  
      if(v && one.length == 8) {  
          var bytesLength = v[0].length;  
          var store = _arr[i].toString(2).slice(7 - bytesLength);  
          for(var st = 1; st < bytesLength; st++) {  
              store += _arr[st + i].toString(2).slice(2);  
          }  
          str += String.fromCharCode(parseInt(store, 2));  
          i += bytesLength - 1;  
      } else {  
          str += String.fromCharCode(_arr[i]);  
      }  
  }  
  return str; 
}
function stringToArrayBuffer(str) {
  var bytes = new Array();
  var len,c;
  len = str.length;
  for(var i = 0; i < len; i++){
      c = str.charCodeAt(i);
      if(c >= 0x010000 && c <= 0x10FFFF){
          bytes.push(((c >> 18) & 0x07) | 0xF0);
          bytes.push(((c >> 12) & 0x3F) | 0x80);
          bytes.push(((c >> 6) & 0x3F) | 0x80);
          bytes.push((c & 0x3F) | 0x80);
      }else if(c >= 0x000800 && c <= 0x00FFFF){
          bytes.push(((c >> 12) & 0x0F) | 0xE0);
          bytes.push(((c >> 6) & 0x3F) | 0x80);
          bytes.push((c & 0x3F) | 0x80);
      }else if(c >= 0x000080 && c <= 0x0007FF){
          bytes.push(((c >> 6) & 0x1F) | 0xC0);
          bytes.push((c & 0x3F) | 0x80);
      }else{
          bytes.push(c & 0xFF);
      }
}
var array = new Int8Array(bytes.length);
for(var i in bytes){
  array[i] =bytes[i];
}
  return array.buffer;
}